BACKGROUNDNeuropathic pain is induced by injury or disease of the nervous system. Most studies have so far focused only on a few known molecules and signaling pathways among neurons. However, all signal transmissions involved in neuropathic pain appear to be an integral system at different molecular levels. This study was designed to screen the differentially expressed genes of the hypothalamus in chronic constriction injury (CCI) rats and analyze their functions in developing neuropathic pain.

METHODSTen adult female Sprague-Dawley rats ((200 +/- 10) g) were used in experimental group and sham group (n = 5 in each group). Mechanical allodynia tests were performed to ensure that the CCI rat model was constructed successfully. Total hypothalamus RNAs were isolated from each group. Forward suppression subtractive hybridization (SSH) library of rat hypothalamus was constructed and up-regulated cDNA clones at neuropathic pain states were obtained via suppressed subtractive hybridization technique and the functions of these genes were analyzed bioinformatically.

RESULTSMechanical allodynia tests showed that the experimental rats had a significantly reduced mechanical allodynia threshold 3 to 13 days after CCI vs sham surgery rats (P < 0.01), indicating that the model was successful. Forward SSH library of the rat hypothalamus was constructed successfully and 26 over-expressed expression sequence tags (ESTs) were obtained from these up-regulated cDNA clones.

CONCLUSIONTwenty-six up-regulated genes, involved in the regulation of cell cycle and apoptosis, signal transduction, and neuroprotection, may play key roles in decreasing mechanical withdraw thresholds in CCI rats, which implicates a multidimensional and integrated molecular mechanism at gene level in developing neuropathic pain with the supraspinal contributions.

Animals ; Computational Biology ; Disease Models, Animal ; Female ; Gene Expression Profiling ; Hypothalamus ; metabolism ; Nitric Oxide ; physiology ; Nucleic Acid Hybridization ; Pain ; metabolism ; Rats ; Rats, Sprague-Dawley ; Sciatic Neuropathy ; metabolism

Objective:To investigate the clinical effect of Chaihu Shugansan combined with abdominal acupuncture on depression caused by chronic pain，and to explore its mechanism. Method:A total of 97 patients with depression caused by chronic pain were randomly divided into control group （49 cases） and observation group （48 cases）. Patients in both groups received routine western medicine treatment，including necessary psychological intervention and taking paroxetine. Control groupobservation groupcontrol group Patients in control group were treated with Xiaoyaowan，and patients in observation group were treated with Chaihu Shugansan combined with abdominal acupuncture. Both groups were treated for 6 weeks. The levels of serum neurotransmitters，cytokines and Hamilton depression rating scale（HAMD） before and after treatment were compared between two groups. Result:There was no significant difference in HAMD scores of the two groups before treatment and the HAMD scores of two groups after treatment were significantly lower than those before treatment （P<0.05），and the HAMD scores in observation group were significantly lower than those in the control group （P<0.05）. There was no significant difference in the levels of serum 5-hydroxytryptamine （5-HT），norepinephrine （NE），and brain-derived neurotrophic factor （BDNF） between two groups before treatment. After treatment，the levels of serum 5-HT，NE，and BDNF in two groups were significantly higher than those before treatment （P<0.05），and the levels in observation group were significantly higher than those in control group （P<0.05）. There was no significant difference in the levels of serum interleukin-6 （IL-6），interleukin-1β （IL-1β） and tumor necrosis factor-α （TNF-α） before treatment. After treatment，the levels of serum IL-6，IL-1β and TNF-α were significantly lower than those before treatment （P<0.05），and the levels in observation group were significantly lower than those in control group （P<0.05）. Conclusion:On the basis of psychological intervention and paroxetine administration，the combination of Chaihu Shugansan and abdominal acupuncture exerts their respective advantages. It treats both symptoms and root causes of depression，relieves the degree of depression，reduces the classification of depression，and regulates the levels of neurotransmitter and cellular inflammatory factors，and inhibits inflammatory response. The clinical effect is significant.